Most miles with stock AFM system?

[clogan2]

I read a lot about deactivating the stock AFM system because of the many reports of trouble. But I often wonder who has accumulated the most trouble-free miles while running the OEM system. I have 114,000 on my '16 Tahoe, and no trouble yet (fingers still crossed).

 

[Pivot]

K N O C K O N W O O D - I put a Range AFM Disabler in mine at what I think was around the 90k mark maybe? Then I had it programmed out with a BlackBear tune at maybe 110-120 or so. Memory is bad but something along those lines.

 

[B-train]

2017 Denali, 6.2L. Purchased at 41k, Range Device at 42k. Current 142K. Oil changes with 5w-30 every 5k-ish

 

[BlackBearPerf]

Just an FYI. In our experience and feedback from customers, most issues the AFM system causes occur with the 2007-2013 models. They still occur with the 2014+ models but not as frequently. Most of our customers with 2014+ models still decide to disable the AFM anyway just to be safe.

 

[Marky Dissod]

The problem is the ON-or-OFF lifters. They are not as robustly designed, spec'd, or constructed, as the true-V8 lifters.

Disabling cylinder deactivation (plugin or ecm reprogram / tune) significantly extends the life of the two-mode lifters -
but even if they are always on, they will never outlast their simpler brethren.
This option is cheap enough that EVERYONE should have already done it.
Most who have disabled cylinder deactivation have been pleasantly surprised by their MpGs.

Also note, that disabling cylinder deactivation greatly extends the life of the torque converter clutch ...

 

[clogan2]

Yep, good to know.
I was just curious as the whether any holdouts had accumulated as much miles as I have while still running the stock system.

I probably should have realized that it is highly unlikely that anyone still running the OEM system will ever see this thread. I'll be surprised if I get any responses at all, now that I think about it.

Oh, well.

 

[Marky Dissod]

The following is my personal experience:
Used to be a livery driver / chauffeur in NYC / NJ / CT, usually driving a 2012 GMC Yukon XL with a 6L80E (started driving it in 2013, it had about 50,000 miles on it already).

I drove it for one year as GM spec'd it, then I had a brilliantly (dumb) idea:
INCREASE V4 mode's duty cycle, to improve the XL's metro / urban and highway MpGs.
Normally V4 mode operates in 5th and 6th gears, with very rare activations in 4th gear.
Had a custom tune written that not only increased V4 mode duty cycle in 4th 5th and 6th, it even allowed some V4 mode in 3rd.
(I could feel it, and hear it if I listened for it, but no one else noticed.)

Although I did save some fuel in the 1st year, fuel consumption increased in the 2nd year.
By the 3rd year, the MpG savings were no better than its original year with GM's OE V4 mode duty cycle.
In the 4th year, despite MONTHLY 0W30 or 5W30 synthetic oil changes (3000 miles or LESS every month), oil consumption became a problem.
My guess:
every time the On/Off cylinders turned off, they got colder than the always-ON cylinders and wore out a bit more quickly than the always-ON cylinders. (I was never able to confirm this theory; there are other possibilities.)
I put on about 40,000 miles every year.

Seems I changed the oil often enough to protect the lifters, but nonetheless could not prevent extra oil consumption.

As a direct result of my experience, on top of the excessive number of failures of other engines with cylinder deactivation,
I will ALWAYS enthusiastically recommend disabling V4 mode, whether by plug-in or by ecm tune.

If your engine still has cylinder deactivation mode (AFM or DFM, whatever), disable it already.

 

[B-train]

The following is my personal experience:
Used to be a livery driver / chauffeur in NYC / NJ / CT, usually driving a 2012 GMC Yukon XL with a 6L80E (started driving it in 2013, it had about 50,000 miles on it already).

I drove it for one year as GM spec'd it, then I had a brilliantly (dumb) idea:
INCREASE V4 mode's duty cycle, to improve the XL's metro / urban and highway MpGs.
Normally V4 mode operates in 5th and 6th gears, with very rare activations in 4th gear.
Had a custom tune written that not only increased V4 mode duty cycle in 4th 5th and 6th, it even allowed some V4 mode in 3rd.
(I could feel it, and hear it if I listened for it, but no one else noticed.)

Although I did save some fuel in the 1st year, fuel consumption increased in the 2nd year.
By the 3rd year, the MpG savings were no better than its original year with GM's OE V4 mode duty cycle.
In the 4th year, despite MONTHLY 0W30 or 5W30 synthetic oil changes (3000 miles or LESS every month), oil consumption became a problem.
My guess:
every time the On/Off cylinders turned off, they got colder than the always-ON cylinders and wore out a bit more quickly than the always-ON cylinders. (I was never able to confirm this theory; there are other possibilities.)
I put on about 40,000 miles every year.

Seems I changed the oil often enough to protect the lifters, but nonetheless could not prevent extra oil consumption.

As a direct result of my experience, on top of the excessive number of failures of other engines with cylinder deactivation,
I will ALWAYS enthusiastically recommend disabling V4 mode, whether by plug-in or by ecm tune.

If your engine still has cylinder deactivation mode (AFM or DFM, whatever), disable it already.

Interesting life experience. I applaud the effort. However, what you experienced is glazed cylinders and carboned/coked cylinder rings. They needed more frequent higher pressures from V8 mode and heat from higher load driving.

 

[Marky Dissod]

Your explanation is almost certainly correct.

Point is, I stopped believing in cylinder deactivation in '17 - which was late already as is.

Anyone still using cylinder deactivation, should already consider themselves well warned.

 

[89Suburban]

I have 351K on my '07 all original engine. I acquired the vehicle @290K and installed the Range device once I joined here and learned about it. I am about halfway saved up to replace this tired azs, leaking old motor. Hopefully before one of these lifters gives up the ghost. Last time I had to run without the Range device for inspection she DID NOT like that for sure!